Closed captioning refers to any system that receives, formats, and displays text on a television or other display to thereby allow viewers to access additional or interpretive information about programming content. Closed captions generally display a transcription of the audio portion of a program as the program progresses, thereby allowing the hearing impaired and others to follow the program content without listening to the audio track associated with the programming.
Federal law mandates that all broadcast television programming in the United States must include closed caption information. For conventional analog NTSC programming, captions are “encoded” into line 21 of the vertical blanking interval (VBI) of the broadcast signal. For conventional digital (e.g., ATSC) programming, several streams are typically encoded in the digital multiplex, including a set of up to sixty-three caption streams encoded in EIA-708 format. Other closed captioning formats or standards may be implemented in the United States or elsewhere. Generally, the closed caption text is provided with the programming content, and the receiver generates text that overlies the received imagery in a “scrolling”, “pop-on” or “paint-on” manner. Motion pictures, video disk (e.g., DVD) content, streamed audio/video, video games and the like may similarly incorporate closed captions using any number of standard or non-standard techniques.
It can be difficult, however, to apply conventional closed captioning techniques in a three-dimensional (or pseudo-three-dimensional) display for several reasons. First, as imagery is processed in more than two dimensions, it becomes increasingly difficult to identify a standard two-dimensional region of the display imagery that is appropriate for presenting closed caption information. Further, because three-dimensional displays are often highly configurable to suit viewer environments and preferences, it can be difficult to identify a standard location for closed caption data. Hence, conventional techniques used to present closed captioning in a two-dimensional viewing space may be unsuitable as three-dimensional displays and content programming become more prevalent.
It is therefore desirable to provide effective closed captioning in a three-dimensional type display. These and other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background section.